title: EGFR and EGFRvIII undergo stress- and EGFR kinase inhibitor-induced mitochondrial translocalization: a potential mechanism of EGFR-driven antagonism of apoptosis.
abstract: BACKGROUND
  Epidermal growth factor receptor (EGFR) plays an essential role in normal development, tumorigenesis and malignant biology of human cancers, and is known to undergo intracellular trafficking to subcellular organelles. Although several studies have shown that EGFR translocates into the mitochondria in cancer cells, it remains unclear whether mitochondrially localized EGFR has an impact on the cells and whether EGFRvIII, a constitutively activated variant of EGFR, undergoes mitochondrial transport similar to EGFR.
  
  
  RESULTS
  We report that both receptors translocate into the mitochondria of human glioblastoma and breast cancer cells, following treatments with the apoptosis inducers, staurosporine and anisomycin, and with an EGFR kinase inhibitor. Using mutant EGFR/EGFRvIII receptors engineered to undergo enriched intracellular trafficking into the mitochondria, we showed that glioblastoma cells expressing the mitochondrially enriched EGFRvIII were more resistant to staurosporine- and anisomycin-induced growth suppression and apoptosis and were highly resistant to EGFR kinase inhibitor-mediated growth inhibition.
  
  
  CONCLUSIONS
  These findings indicate that apoptosis inducers and EGFR-targeted inhibitors enhance mitochondrial translocalization of both EGFR and EGFRvIII and that mitochondrial accumulation of these receptors contributes to tumor drug resistance. The findings also provide evidence for a potential link between the mitochondrial EGFR pathway and apoptosis.
authors.affiliation: Division of Surgical Sciences, Department of Surgery, Duke University School of Medicine, 433A MSRB I, 103 Research Drive, Durham, NC 27710, USA.
authors.forename: Xinyu
authors.initials: X
authors.lastname: Cao
authors.forename: Hu
authors.initials: H
authors.lastname: Zhu
authors.forename: Francis
authors.initials: F
authors.lastname: Ali-Osman
authors.forename: Hui-Wen
authors.initials: HW
authors.lastname: Lo
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D019943:Amino Acid Substitution / Q000235:genetics; D017209:Apoptosis / Q000187:drug effects*; D045744:Cell Line, Tumor; D017124:Conserved Sequence / Q000235:genetics; D019008:Drug Resistance, Neoplasm / Q000187:drug effects; D066246:ErbB Receptors / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000378:metabolism; D000077156:Gefitinib; D006801:Humans; D008928:Mitochondria / Q000187:drug effects* / Q000201:enzymology*; D008969:Molecular Sequence Data; D050505:Mutant Proteins / Q000378:metabolism; D047428:Protein Kinase Inhibitors / Q000494:pharmacology*; D021381:Protein Transport / Q000187:drug effects; D011799:Quinazolines / Q000494:pharmacology
chemical_list: D050505:Mutant Proteins; D047428:Protein Kinase Inhibitors; D011799:Quinazolines; C410723:epidermal growth factor receptor VIII; D066246:ErbB Receptors; D000077156:Gefitinib